New types of memory have demonstrated significant potential to compete with commonly utilized types of memory. For example, non-volatile spin-transfer torque random access memory (referred to herein as “STRAM”) has been discussed as a “universal” memory. The ability of STRAM to more effectively compete with established memory types, such as FLASH memory (NAND or NOR) can be maximized by either decreasing the current density required by STRAM or by increasing the density at which STRAM cells can be formed on a chip.
Generally, STRAM cells are constructed using photolithographic techniques. Conventional optical lithographic techniques can be described by a factor, K1, that relates to both process parameters and material parameters. K1 can be utilized to calculate the minimum feature size that can be achieved using a photolithographic process with a given set of conditions and materials using Equation 1.
                              C          ⁢                                          ⁢                      D            min                          =                                            K              1                        ⁢            λ                    NA                                    Equation        ⁢                                  ⁢        1            In Equation 1, CDmin is the minimum critical dimension that can be obtained with photolithography at the disclosed conditions; K1 is a factor related to materials and processes; λ is the wavelength of energy being used in the photolithography; and NA is the numerical aperture of the utilized lens. K1 is typically greater than 0.30 in commonly utilized photolithography processes; as seen from Equation 1, one method of decreasing the minimum feature size that can be fabricated is to decrease K1.